DRAINING RUNNING SANDS. 125 



as short a space as possible, and tlie third immediately fol- 

 lowing- with the bottoms and covering-. The main drains are 

 laid either with large-sized tiles and bottoms, or with two 

 common ones, one upon the other, the lower one being* 

 reversed, and the u])per placed upon its edges half the 

 length of the tile backward, that the ends of the upper and 

 lower tiles may not come together, which Avill break the 

 joinings throughout the whole drain. If the latter plan be 

 adopted, the minor drains are laid level with the edges of 

 the reversed tile ; if the former, about 2 inches descent is 

 given at the entrance of the main drain. 



All rapid falls are particularly avoided, or the drain will 

 wash away in spite of all precaution, especially where a strong- 

 run of water occurs. Where a fall of one in a hundred cannot 

 be avoided, it is necessary to beat clay into the bottom of the 

 drain under the soles. In setting out the minor drains, the 

 distance of each is regulated, as already pointed out, accord- 

 ing- to the openness of the land and the depth of the water. 

 All long- runs are also avoided, the length being no more 

 than from 3 to 5 chains. I need scarcely say that the whole 

 of the laud is thrown level, so that there is neither ridge nor 

 fiuTow to regard. 



We shall now consider the most important and critical 

 part of the work, which is the taking out of the bottom spit, 

 and the laying of the tiles and bottoms ; but most of all, the ■ 

 securing- of the tiles from admitting the quick running- sand. 

 The two men who cut the drain to its proper depth, work as 

 near to each other as possible, and the tile-layer cpiite up to 

 the latter, or the drain woidd be immediately closed up by 

 the sand running- in from the sides, which would also let 

 down the mass from the surface. In other words, when the 

 first man has got a few feet from the end of the drain, the 

 second commences taking- out the bottom spit, and as soon 

 as he has made way for the laying- of three or four tiles, it is 

 immediately done by the tile-layer; first laying the bottoms 

 quite close to each other, and upon them the tiles, leaving- 

 as little crevice as possible, and immediately covering- them 

 with about 4 inches of the most tenacious soil that can be 

 procured. Clay would be used, but on account of its being- 

 in large hard lumps, it cannot be made to bed sufficiently 

 close to keep out the sand. Here I must notice, that it is 

 essentially necessary that the drains be cut 3 or 4 

 inches wider at the bottom than the width of the tile, so as 

 to admit this strong- soil down the sides to the very bottom. 



